What exactly is the Metaverse?

I've seen this word over and over, from Unity Blog, to Hideo Kojima's Twitter, and many other places.
They all seem to be talking about different thing, Googling it gave me a lot of different definition of what Metaverse is.

I have a hard time understanding what exactly it is.

Is it something Facebook will be releasing?
Is it Mixed Reality environment?
Is it a shared VR space?
Is it a shared digital space?
Is it a new industry?
Is it an environment to use your NFTs?

Why is it every time...

What exactly is the Metaverse?